Special Features

Current Special Features

Research in the biological effects of ocean acidification has accelerated rapidly over the past decade, and more complex ecological and evolutionary questions are now being addressed compared with the many short-term, single-species and single-stressor experiments that marked the beginning of the field. This Special Feature addresses cutting-edge questions in ocean acidification research, across the taxonomic spectrum from plankton to top predators. The nine papers cover three streams of research identified as crucial to predicting the impacts of ocean acidification: (i) the relationship with other environmental drivers, (ii) the effects on ecological process and species interactions, and (iii) the role that individual variation, phenotypic plasticity and adaptation will have in shaping the impacts of ocean acidification. The papers illustrate the importance of interactions between species and the interacting effects of ocean warming in shaping the ecological effects of ocean acidification. They also illustrate the need for an increased focus on the capacity for marine organisms to acclimate and adapt to ocean acidification, and what constraints to adaptation may exist, in order to improve our predictions about the effects of ocean acidification on marine ecosystems.

Fossils have always had a special place in phylogeny. Historically, their position as potential ancestors gave them greater weight in establishing the broad structure of the tree of life. As phylogenetic systematics advanced, the increasing availability of sequence data meant morphology, and consequently fossils, were often excluded from analyses of modern lineages, relegated to serving only as calibrations for dating branching events. However, the past decade has seen a major acceleration in the development, and deployment, of new methodologies for inferring phylogenies containing living and extinct taxa, and using information about sampling of the fossil record to date divergences. These new methods promise to resolve long-standing conflicts between morphological and molecular estimates of relationships, as well as between molecular clock and fossil record estimates of divergence times. However, their novelty also means they are not yet well understood. The nine papers of this Special Feature gather together both biologists and paleontologists to tackle these fundamental questions of how to assemble a tree of life that both acknowledges and leverages the fossil record, and the considerable promise for phylogenies containing fossil taxa to address major questions of ecology and evolution in deep time.

The study of extinction has become an increasingly pressing concern over the last few decades. Methodological advances, the accessibility of large datasets, and the strengthening of ties between ecology and palaeontology have together transformed the field. This Special Feature presents state-of-the-art research that is rigorously quantitative and focused on well-defined questions from the science of extinction biology. Methods of inferring and predicting species losses are major themes, and researchers now draw on a wide array of data sources including spatial distributions of presences, population size time series, molecular sequences, and fossil occurrences. Examples of the many specific topics include demonstrating selective factors, quantifying extinction debt, putting probabilities on individual extinction events, using palaeontological data to predict future extinctions, and studying mass extinctions in the deep-time fossil record. Together, this body of work shows how extinction biology has transformed itself into a distinct and dynamic sub-discipline with practical implications for conservation biology and global change.

Previous Special Features

Most marine species inhabit a patchy world, where populations are connected to one another through the migration and dispersal of individuals at particular life-history stages. Recent research, both theoretical and empirical, on connectivity of metapopulations has challenged the established paradigm that marine populations are largely “open,” leading to growing recognition that self-recruitment may be common and new insights into the evolutionary consequences of living in a patchy world and the design of marine protected areas. This Special Feature explores the state of “Marine Movement Ecology” from small invertebrates to the largest fish, inhabiting benthic and pelagic realms. While the papers are diverse in terms of systems or approaches, each addresses the central theme: what are the mechanisms and consequences of migration or dispersal in marine habitats?

W. D. Hamilton FRS was one of the twentieth century’s intellectual giants, and with this Special Feature we note the 50th anniversary of his seminal contributions that established inclusive fitness as a central element of Darwinian evolution. The authors contributing to this Special Feature present work that traces in some way to Hamilton’s oeuvre; looking back further, Costa’s contribution links Hamilton’s work to Darwin’s and shows how he not only extended Darwin’s concept of natural selection but also provided the framework within which it could ramify. The 1963–1964 papers that we celebrate here provide an elegant solution to a nagging problem, the evolution of altruistic behaviour.

Recent decades have seen a significant rise in studies in which evolution is observed and analysed directly - as it happens — under replicated, controlled conditions. Such 'experimental evolution' approaches offer a degree of resolution of evolutionary processes and their underlying genetics that is difficult or even impossible to achieve in more traditional comparative and retrospective analyses. In principle, experimental populations can be monitored for phenotypic and genetic changes with any desired level of replication and measurement precision, facilitating progress on fundamental and previously unresolved questions in evolutionary biology. This special feature brings together 10 invited papers in which experimental evolution is making significant progress on a variety of fundamental questions.

The history of life on this planet is gleaned from analyzing how fossils are distributed through time and space. While these patterns are now rather securely known, at least for well-studied parts of the world, their interpretation remains far from simple. Fossils preserve only partial data from which to reconstruct their biology, and the geological record is incomplete and biased, so that taxonomic ranges and palaeocommunity structure are imperfectly known. To better understand the often highly complex deep-time processes that gave rise to the empirical fossil record, palaeontologists have turned to modelling the past. This Special Feature brought together a series of 11 papers that showcased how modelling the past is being applied to advance our understanding across a wide spectrum of current palaeontological endeavours.

In this Special Feature, we explore how observation and analysis of naturally occurring behaviour are contributing to our understanding of animal cognition. Observational data may be necessary for several reasons: because certain types of behaviour, or certain species simply do not lend themselves to study in captivity; because certain questions, or certain settings do not allow the manipulation of variables necessary for experiments; or any combination of these problems. We shall illustrate how novel recording, statistical and analytical methods have led to advances in our understanding of several topics that cannot be fully understood with experiments alone. Specifically, we highlight: complex alliance formation in dolphins; gestural communication in apes; imitation of novel actions and pantomime; innovation in comparative perspective; the elaborate manual skills involved in chimpanzee tool use; elephant cognition; and the planning of travel routes and foraging decisions by primates.